diff mbox

[RFC,03/39] drm/i915: Explicit power enable during deferred context initialisation

Message ID 1437143628-6329-4-git-send-email-John.C.Harrison@Intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

John Harrison July 17, 2015, 2:33 p.m. UTC
From: John Harrison <John.C.Harrison@Intel.com>

A later patch in this series re-organises the batch buffer submission
code. Part of that is to reduce the scope of a pm_get/put pair.
Specifically, they previously wrapped the entire submission path from
the very start to the very end, now they only wrap the actual hardware
submission part in the back half.

While that is a good thing in general, it causes a problem with the
deferred context initialisation. That is done quite early on in the
execbuf code path - it happens at context validation time rather than
context switch time. Some of the deferred work requires the power to
be enabled. Hence this patch adds an explicit power reference count to
the deferred initialisation code itself.

Change-Id: Id7b1535dfd8809a2bd5546272de2bbec39da2868
Issue: GMINL-5159
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

Comments

Daniel Vetter July 21, 2015, 7:54 a.m. UTC | #1
On Fri, Jul 17, 2015 at 03:33:12PM +0100, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
> 
> A later patch in this series re-organises the batch buffer submission
> code. Part of that is to reduce the scope of a pm_get/put pair.
> Specifically, they previously wrapped the entire submission path from
> the very start to the very end, now they only wrap the actual hardware
> submission part in the back half.
> 
> While that is a good thing in general, it causes a problem with the
> deferred context initialisation. That is done quite early on in the
> execbuf code path - it happens at context validation time rather than
> context switch time. Some of the deferred work requires the power to
> be enabled. Hence this patch adds an explicit power reference count to
> the deferred initialisation code itself.

The main reason for grabbing rpm for the entire execbuf is writing ptes
for global gtt. This happens on gen6 due to some hilarious tlb aliasing hw
bug where we have to bind objects into both ggtt and ppgtt.
-Daniel

> 
> Change-Id: Id7b1535dfd8809a2bd5546272de2bbec39da2868
> Issue: GMINL-5159
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
>  drivers/gpu/drm/i915/intel_lrc.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 18dbd5c..8aa9a18 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -2317,12 +2317,15 @@ int intel_lr_context_deferred_create(struct intel_context *ctx,
>  	WARN_ON(ctx->legacy_hw_ctx.rcs_state != NULL);
>  	WARN_ON(ctx->engine[ring->id].state);
>  
> +	intel_runtime_pm_get(dev->dev_private);
> +
>  	context_size = round_up(get_lr_context_size(ring), 4096);
>  
>  	ctx_obj = i915_gem_alloc_object(dev, context_size);
>  	if (!ctx_obj) {
>  		DRM_DEBUG_DRIVER("Alloc LRC backing obj failed.\n");
> -		return -ENOMEM;
> +		ret = -ENOMEM;
> +		goto error_pm;
>  	}
>  
>  	if (is_global_default_ctx) {
> @@ -2331,7 +2334,7 @@ int intel_lr_context_deferred_create(struct intel_context *ctx,
>  			DRM_DEBUG_DRIVER("Pin LRC backing obj failed: %d\n",
>  					ret);
>  			drm_gem_object_unreference(&ctx_obj->base);
> -			return ret;
> +			goto error_pm;
>  		}
>  	}
>  
> @@ -2415,6 +2418,7 @@ int intel_lr_context_deferred_create(struct intel_context *ctx,
>  		ctx->rcs_initialized = true;
>  	}
>  
> +	intel_runtime_pm_put(dev->dev_private);
>  	return 0;
>  
>  error:
> @@ -2428,6 +2432,8 @@ error_unpin_ctx:
>  	if (is_global_default_ctx)
>  		i915_gem_object_ggtt_unpin(ctx_obj);
>  	drm_gem_object_unreference(&ctx_obj->base);
> +error_pm:
> +	intel_runtime_pm_put(dev->dev_private);
>  	return ret;
>  }
>  
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 18dbd5c..8aa9a18 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -2317,12 +2317,15 @@  int intel_lr_context_deferred_create(struct intel_context *ctx,
 	WARN_ON(ctx->legacy_hw_ctx.rcs_state != NULL);
 	WARN_ON(ctx->engine[ring->id].state);
 
+	intel_runtime_pm_get(dev->dev_private);
+
 	context_size = round_up(get_lr_context_size(ring), 4096);
 
 	ctx_obj = i915_gem_alloc_object(dev, context_size);
 	if (!ctx_obj) {
 		DRM_DEBUG_DRIVER("Alloc LRC backing obj failed.\n");
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto error_pm;
 	}
 
 	if (is_global_default_ctx) {
@@ -2331,7 +2334,7 @@  int intel_lr_context_deferred_create(struct intel_context *ctx,
 			DRM_DEBUG_DRIVER("Pin LRC backing obj failed: %d\n",
 					ret);
 			drm_gem_object_unreference(&ctx_obj->base);
-			return ret;
+			goto error_pm;
 		}
 	}
 
@@ -2415,6 +2418,7 @@  int intel_lr_context_deferred_create(struct intel_context *ctx,
 		ctx->rcs_initialized = true;
 	}
 
+	intel_runtime_pm_put(dev->dev_private);
 	return 0;
 
 error:
@@ -2428,6 +2432,8 @@  error_unpin_ctx:
 	if (is_global_default_ctx)
 		i915_gem_object_ggtt_unpin(ctx_obj);
 	drm_gem_object_unreference(&ctx_obj->base);
+error_pm:
+	intel_runtime_pm_put(dev->dev_private);
 	return ret;
 }